Tumor suppressor candidate 3 (TUSC3)

Tumor suppressor candidate 3 (TUSC3) is an integral membrane protein of the endoplasmic reticulum and a non-catalytic subunit of the oligosaccharyltransferase complex, which is pivotal for N-linked glycosylation of proteins—a modification important for protein folding, stability, and function[1][2][4]. TUSC3 also facilitates magnesium transport across membranes, contributing to cellular magnesium homeostasis[2][4]. In cancer biology, TUSC3 is frequently deleted, mutated, or epigenetically silenced in multiple epithelial malignancies (notably prostate, ovarian, colorectal, and breast cancers), with its loss promoting cell proliferation, migration, invasion, and resistance to ER stress-induced apoptosis; these functions underline its role as a tumor suppressor[1][3][4]. Additionally, loss-of-function mutations in TUSC3 are a cause of autosomal recessive intellectual disability[2][4]. Currently, no approved drugs directly target TUSC3, but its loss is recognized as a clinically relevant biomarker for cancer progression and prognosis through detection of gene deletion or promoter hypermethylation[2][3].

Other names

Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit TUSC3N33Oligosaccharyl transferase subunit TUSC3MGC13453OST3AMRT7MagT2SLC58A2Magnesium uptake/transporter TUSC3Protein N33D8S1992M33MRT22oligosaccharyltransferase 3 homolog A (S. cerevisiae)

Not directly drug-targeted (no approved drugs), but as a tumor suppressor, loss or silencing can contribute to drug resistance or sensitivity to agents inducing ER stress